115 citations · 847 across the 17 of their papers we have counts for
17 papers
A differentiable programming method for quantum control
Frank Schäfer, Michal Kloc, Christoph Bruder +1
Optimal control is highly desirable in many current quantum systems, especially to realize tasks in quantum information processing. We introduce a method based on differentiable pr…
Unsupervised identification of topological order using predictive models
Eliska Greplova, Agnes Valenti, Gregor Boschung +3
Machine-learning driven models have proven to be powerful tools for the identification of phases of matter. In particular, unsupervised methods hold the promise to help discover ne…
Heralded dissipative preparation of nonclassical states in a Kerr oscillator
Martin Koppenhöfer, Christoph Bruder, Niels Lörch
We present a heralded state preparation scheme for driven nonlinear open quantum systems. The protocol is based on a continuous photon counting measurement of the system's decay ch…
Quantum state preparation for coupled period tripling oscillators
Niels Lörch, Yaxing Zhang, Christoph Bruder +1
We investigate the quantum transition to a correlated state of coupled oscillators in the regime where they display period tripling in response to a drive at triple the eigenfreque…
Divergence of predictive model output as indication of phase transitions
Frank Schäfer, Niels Lörch
We introduce a new method to identify phase boundaries in physical systems. It is based on training a predictive model such as a neural network to infer a physical system's paramet…
Nonlinear Quantum Behavior of Ultrashort-Pulse Optical Parametric Oscillators
Tatsuhiro Onodera, Edwin Ng, Chris Gustin +6
The quantum features of ultrashort-pulse optical parametric oscillators (OPOs) are investigated theoretically in the nonlinear regime near and above threshold. Viewing the pulsed O…
Interaction-induced time-symmetry breaking in driven quantum oscillators
M. I. Dykman, Christoph Bruder, Niels Lörch +1
We study parametrically driven quantum oscillators and show that, even for weak coupling between the oscillators, they can exhibit various many-body states with broken time-transla…
Optimal work extraction from quantum states by photo-assisted Cooper pair tunneling
Niels Lörch, Christoph Bruder, Nicolas Brunner +1
The theory of quantum thermodynamics predicts fundamental bounds on work extraction from quantum states. As these bounds are derived in a very general and abstract setting, it is u…
Quantum effects in amplitude death of coupled anharmonic self-oscillators
Ehud Amitai, Martin Koppenhöfer, Niels Lörch +1
Coupling two or more self-oscillating systems may stabilize their zero-amplitude rest-state, therefore quenching their oscillation. This phenomenon is termed "amplitude death". Wel…
Quantum Synchronization Blockade: Energy Quantization hinders Synchronization of Identical Oscillators
Niels Lörch, Simon E. Nigg, Andreas Nunnenkamp +2
Classically, the tendency towards spontaneous synchronization is strongest if the natural frequencies of the self-oscillators are as close as possible. We show that this wisdom fai…
Robust quantum optimizer with full connectivity
Simon E. Nigg, Niels Loerch, Rakesh P. Tiwari
Quantum phenomena have the potential to speed up the solution of hard optimization problems. For example quantum annealing, based on the quantum tunneling effect, has recently been…
Optomechanical Self-Oscillations in an Anharmonic Potential: Engineering a Nonclassical Steady State
Manuel Grimm, Christoph Bruder, Niels Lörch
We study self-oscillations of an optomechanical system, where coherent mechanical oscillations are induced by a driven optical or microwave cavity, for the case of an anharmonic me…
Genuine quantum signatures in synchronization of anharmonic self-oscillators
Niels Lörch, Ehud Amitai, Andreas Nunnenkamp +1
We study the synchronization of a van der Pol self-oscillator with Kerr anharmonicity to an external drive. We demonstrate that the anharmonic, discrete energy spectrum of the quan…
Quantum Algorithmic Readout in Multi-Ion Clocks
Marius Schulte, Niels Lörch, Ian D. Leroux +2
Optical clocks based on ensembles of trapped ions offer the perspective of record frequency uncertainty with good short-term stability. Most suitable atomic species lack closed tra…
Laser Theory for Optomechanics: Limit Cycles in the Quantum Regime
Niels Lörch, Jiang Qian, Aashish Clerk +2
Optomechanical systems can exhibit self-sustained limit cycles where the quantum state of the mechanical resonator possesses nonclassical characteristics such as a strongly negativ…
Precision spectroscopy by photon-recoil signal amplification
Yong Wan, Florian Gebert, Jannes B. Wübbena +7
Precision spectroscopy of atomic and molecular ions offers a window to new physics, but is typically limited to species with a cycling transition for laser cooling and detection. Q…
Wave Function Renormalization Effects in Resonantly Enhanced Tunneling
N. Lörch, F. V. Pepe, H. Lignier +8
We study the time evolution of ultra-cold atoms in an accelerated optical lattice. For a Bose- Einstein condensate with a narrow quasi-momentum distribution in a shallow optical la…